Step 1: Open start menu 

Step 2: Open control panel

Step 3: open regional settings

Step 4: Click and open additional settings

Step 5 & 6: Decimal symbol must be a dot (.)  and List separator must be a comma (,)

Step 7 & 8: Open start menu and type excel and open it

Step 9: on Excel click and open file on the top ribbon

Step 10: Click and open Options

Step 11 & 12: Click and open advance, scroll to Use system separators and tick it and make sure on Decimal is a dot (.) and Thousands separator is a comma (,)